Liquid Crystal Display (LCD) screens are used in a variety of devices given their size, relatively low cost, and high resolution. Such devices typically include portable electronic devices and non-portable electronic devices. Portable electronic devices may include laptop computers, cell phones, pagers, personal digital assistants, and the like, while non-portable electronic devices make include televisions, desktop PCs, industrial controls, and the like. While such non-portable electronic devices consume modest amounts of power individually, in combination they consume a significant amount of power. Any improvements therefore in the energy efficiency of such non-portable devices are therefore desirable.
Manufacturers are also constantly striving to reduce power consumption of portable electronic devices without degradation of performance. Such portable devices are typically powered by some type of battery, but may be powered with other voltage sources such as a solar source. In the case of a rechargeable battery powered portable electronic devices, reduced power consumption enables the device to operate for longer periods of time between charging of the battery and/or to have a smaller size battery.
Typically, the LCD panel that drives an LCD of an electronic device and its backlight receives voltage directly from the power source of the electronic device. For example, the power source may be a battery for a portable electronic device. This decreases energy efficiency for such devices when select load modules such as the backlight and/or the LCD panel do not need the full available voltage from the power source.
Accordingly, there is a need in the art for an adaptive power supply circuit that overcomes the above deficiencies in the prior art to allow for appropriate power supply levels to be applied to select load modules.